Question about rebuilding rear calipers, 1985 2m4. (Page 1/1)
Mikeq716 MAY 09, 11:27 PM
Hello everyone,

Recently, I purchased a 1985 2m4 from a friend as a project car, to keep as a 4 cylinder, and restore it back to what it was. One of the issues the car had, was no emergency brake. I have replaced all of the emergency brake cables, but in the process, a buddy attempted to compress one of the pistons without using the correct tool to spin it back in. Needless to say the caliper started leaking. I decided that I would take both rear calipers off at this point and rebuild them because of the age of the car and the importance of being able to stop. I removed the calipers, and took them apart. Instead of using air to remove the pistons, i used a 2x4 and gently tapped them out via the spinning bolt on the back of the caliper. I will upload pictures of the calipers, and the pistons. My question is are the calipers and pistons worth rebuilding? As the t shaped piece that sits in the pistons were not even between the 2, i gently tapped them so that they were even. I hope I have explained the situation in enough detail, if not please let me know and I will ellaborate.

Thank you so much, Mike






[This message has been edited by Mikeq716 (edited 05-09-2021).]

theogre MAY 10, 04:09 AM
First mistake is turning a piston to retract them.

Shell maybe ok
Piston is not. That "dirt" on outside where hydro seal works is so bad likely new seal will not last if seals at all.
can't tell if back is pushed out and don't have my notes...
But doesn't matter if Front is broken.

Not sure what said above... You mean you hit/pushed the piston back cover where park brake screw works?
If true the Piston "guts" are F'd even before you started the job.

See my Cave, Rear Brakes, Clamp Method notes & Brake Service to start...

Rebuild "kits" only works to fix bad seals etc. for the shells w/ good pistons.
Bad Rear pistons are not made for "rebuilding" no matter what the "internet" says.

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Dennis LaGrua MAY 14, 08:08 PM

quote
Originally posted by theogre:

First mistake is turning a piston to retract them.




Yes that's correct but you can remove the parking brake lever and twist the screw that enters the piston. You can do this by hand and its quite easy to retract the piston. Just need to remember to put the seal and washer back in the right order when done. If you wish to rebuild you may be able to find new pistons and seals but you will need to hone the caliper bore smooth. If those are too pitted then the rebuild will not be successful. Fiero brake calipers that work are getting hard to find and rebuild.

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